30 UNRECORDED AND OTHER MINERALS 



61 ScAPOLiTE. — (Hydrous silicate of alu7ninium and cal- 

 cium.^ 



This mineral was found as loosened rounded boulders 

 in a seam of asbestos occurring in the serpentine at 

 Anderson's Creek, near Beaconsfield. It was mis- 

 taken by the miners for quartz, which it somewhat 

 resembles. It has, however, a slightly greenish 

 tinge, and its hardness is only between 5 and 6. It 

 is soluble with difficulty in HCl. 



Microscopical characters. — Confusedly crystalline, 

 with the larger crystal faces obscurely divergent. 

 The crystals often form rosettes. Double refrac- 

 tion, strong ; interference colours higher than 

 quartz; extinction straight in longitudinal sec- 

 tions; no sensible absorption. 



Scapolite is mostly found in schists and gneiss. It 

 also occurs in amphibolites and ophites. When it 

 is found in gabbro, it has been derived from 

 felspar, and this may have been the case here, 

 though there is some reason to believe that the 

 serpentine was originally pyroxenite. Scapolite is 

 undeniably a secondary mineral, and was here 

 formed during the hydro-metamorphic process of 

 serpentinisation. (W. II. Twelvetrees.) 



62 ScHEELiTE. — (Tungstate of calcium.) 



Analysis of a sample of this mineral from Mt. Ram- 

 say : — 



W O2 = 79-77 

 M O3 = trace 

 Ca O = 19 65 



99-42 



(Dana, ' System, of Mineralogy," page 987.) 



63 ScHROTTERiTE. — {Hydfous aluminium silicate.) 



A soft brittle white to honey-yellow coloured gum- 

 like substance, occurring as an incrustation and 

 in patches in a fissure in Silurian slate. It decom- 

 poses to a white powder. Occasionally it is stalac- 

 titic or mamillated, and easily falls to pieces. 

 Obtained near the Pieman River. 



